/*
Copyright The Helm Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package main

import (
	"fmt"
	"io"
	"os"
	"path/filepath"

	"github.com/spf13/cobra"

	"helm.sh/helm/v3/cmd/helm/require"
)

const completionDesc = `
Generate autocompletions script for Helm for the specified shell.
`
const bashCompDesc = `
Generate the autocompletion script for Helm for the bash shell.

To load completions in your current shell session:
$ source <(helm completion bash)

To load completions for every new session, execute once:
Linux:
  $ helm completion bash > /etc/bash_completion.d/helm
MacOS:
  $ helm completion bash > /usr/local/etc/bash_completion.d/helm
`

const zshCompDesc = `
Generate the autocompletion script for Helm for the zsh shell.

To load completions in your current shell session:
$ source <(helm completion zsh)

To load completions for every new session, execute once:
$ helm completion zsh > "${fpath[1]}/_helm"
`

func newCompletionCmd(out io.Writer) *cobra.Command {
	cmd := &cobra.Command{
		Use:   "completion",
		Short: "generate autocompletions script for the specified shell",
		Long:  completionDesc,
		Args:  require.NoArgs,
	}

	bash := &cobra.Command{
		Use:                   "bash",
		Short:                 "generate autocompletions script for bash",
		Long:                  bashCompDesc,
		Args:                  require.NoArgs,
		DisableFlagsInUseLine: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			return runCompletionBash(out, cmd)
		},
	}

	zsh := &cobra.Command{
		Use:                   "zsh",
		Short:                 "generate autocompletions script for zsh",
		Long:                  zshCompDesc,
		Args:                  require.NoArgs,
		DisableFlagsInUseLine: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			return runCompletionZsh(out, cmd)
		},
	}

	cmd.AddCommand(bash, zsh)

	return cmd
}

func runCompletionBash(out io.Writer, cmd *cobra.Command) error {
	err := cmd.Root().GenBashCompletion(out)

	// In case the user renamed the helm binary (e.g., to be able to run
	// both helm2 and helm3), we hook the new binary name to the completion function
	if binary := filepath.Base(os.Args[0]); binary != "helm" {
		renamedBinaryHook := `
# Hook the command used to generate the completion script
# to the helm completion function to handle the case where
# the user renamed the helm binary
if [[ $(type -t compopt) = "builtin" ]]; then
    complete -o default -F __start_helm %[1]s
else
    complete -o default -o nospace -F __start_helm %[1]s
fi
`
		fmt.Fprintf(out, renamedBinaryHook, binary)
	}

	return err
}

func runCompletionZsh(out io.Writer, cmd *cobra.Command) error {
	zshInitialization := `#compdef helm

__helm_bash_source() {
	alias shopt=':'
	alias _expand=_bash_expand
	alias _complete=_bash_comp
	emulate -L sh
	setopt kshglob noshglob braceexpand
	source "$@"
}
__helm_type() {
	# -t is not supported by zsh
	if [ "$1" == "-t" ]; then
		shift
		# fake Bash 4 to disable "complete -o nospace". Instead
		# "compopt +-o nospace" is used in the code to toggle trailing
		# spaces. We don't support that, but leave trailing spaces on
		# all the time
		if [ "$1" = "__helm_compopt" ]; then
			echo builtin
			return 0
		fi
	fi
	type "$@"
}
__helm_compgen() {
	local completions w
	completions=( $(compgen "$@") ) || return $?
	# filter by given word as prefix
	while [[ "$1" = -* && "$1" != -- ]]; do
		shift
		shift
	done
	if [[ "$1" == -- ]]; then
		shift
	fi
	for w in "${completions[@]}"; do
		if [[ "${w}" = "$1"* ]]; then
			# Use printf instead of echo beause it is possible that
			# the value to print is -n, which would be interpreted
			# as a flag to echo
			printf "%s\n" "${w}"
		fi
	done
}
__helm_compopt() {
	true # don't do anything. Not supported by bashcompinit in zsh
}
__helm_ltrim_colon_completions()
{
	if [[ "$1" == *:* && "$COMP_WORDBREAKS" == *:* ]]; then
		# Remove colon-word prefix from COMPREPLY items
		local colon_word=${1%${1##*:}}
		local i=${#COMPREPLY[*]}
		while [[ $((--i)) -ge 0 ]]; do
			COMPREPLY[$i]=${COMPREPLY[$i]#"$colon_word"}
		done
	fi
}
__helm_get_comp_words_by_ref() {
	cur="${COMP_WORDS[COMP_CWORD]}"
	prev="${COMP_WORDS[${COMP_CWORD}-1]}"
	words=("${COMP_WORDS[@]}")
	cword=("${COMP_CWORD[@]}")
}
__helm_filedir() {
	local RET OLD_IFS w qw
	__debug "_filedir $@ cur=$cur"
	if [[ "$1" = \~* ]]; then
		# somehow does not work. Maybe, zsh does not call this at all
		eval echo "$1"
		return 0
	fi
	OLD_IFS="$IFS"
	IFS=$'\n'
	if [ "$1" = "-d" ]; then
		shift
		RET=( $(compgen -d) )
	else
		RET=( $(compgen -f) )
	fi
	IFS="$OLD_IFS"
	IFS="," __debug "RET=${RET[@]} len=${#RET[@]}"
	for w in ${RET[@]}; do
		if [[ ! "${w}" = "${cur}"* ]]; then
			continue
		fi
		if eval "[[ \"\${w}\" = *.$1 || -d \"\${w}\" ]]"; then
			qw="$(__helm_quote "${w}")"
			if [ -d "${w}" ]; then
				COMPREPLY+=("${qw}/")
			else
				COMPREPLY+=("${qw}")
			fi
		fi
	done
}
__helm_quote() {
	if [[ $1 == \'* || $1 == \"* ]]; then
		# Leave out first character
		printf %q "${1:1}"
	else
		printf %q "$1"
	fi
}
autoload -U +X bashcompinit && bashcompinit
# use word boundary patterns for BSD or GNU sed
LWORD='[[:<:]]'
RWORD='[[:>:]]'
if sed --help 2>&1 | grep -q 'GNU\|BusyBox'; then
	LWORD='\<'
	RWORD='\>'
fi
__helm_convert_bash_to_zsh() {
	sed \
	-e 's/declare -F/whence -w/' \
	-e 's/_get_comp_words_by_ref "\$@"/_get_comp_words_by_ref "\$*"/' \
	-e 's/local \([a-zA-Z0-9_]*\)=/local \1; \1=/' \
	-e 's/flags+=("\(--.*\)=")/flags+=("\1"); two_word_flags+=("\1")/' \
	-e 's/must_have_one_flag+=("\(--.*\)=")/must_have_one_flag+=("\1")/' \
	-e "s/${LWORD}_filedir${RWORD}/__helm_filedir/g" \
	-e "s/${LWORD}_get_comp_words_by_ref${RWORD}/__helm_get_comp_words_by_ref/g" \
	-e "s/${LWORD}__ltrim_colon_completions${RWORD}/__helm_ltrim_colon_completions/g" \
	-e "s/${LWORD}compgen${RWORD}/__helm_compgen/g" \
	-e "s/${LWORD}compopt${RWORD}/__helm_compopt/g" \
	-e "s/${LWORD}declare${RWORD}/builtin declare/g" \
	-e "s/\\\$(type${RWORD}/\$(__helm_type/g" \
	-e 's/aliashash\["\(.\{1,\}\)"\]/aliashash[\1]/g' \
	-e 's/FUNCNAME/funcstack/g' \
	<<'BASH_COMPLETION_EOF'
`
	out.Write([]byte(zshInitialization))

	runCompletionBash(out, cmd)

	zshTail := `
BASH_COMPLETION_EOF
}
__helm_bash_source <(__helm_convert_bash_to_zsh)
`
	out.Write([]byte(zshTail))
	return nil
}
